Field of the Invention
The present invention relates to a light source device and a projector having the light source device.
Description of the Related Art
Recently, data projectors are often used as imaging apparatuses for projecting screens of personal computers, video screens, images based on image data stored in memory cards and the like, and so on onto screens. Such projectors are for concentrating light emitted from light sources on a micromirror display element called DMD (Digital Micromirror Device) or a liquid crystal panel and displaying color images on a screen.
In the related art, in such projectors, projectors using high-luminance discharge lamps as light sources predominated; however, recently, various projectors using other light sources such as light emitting diodes, laser diodes, organic EL, or phosphors have been developed.
JP-A-2017-9684 discloses a projector, which includes a red light source device, and an optical wheel device having a fluorescent area which emits fluorescent light of a green wavelength band if being irradiated with light of a blue wavelength band emitted as excitation light from an excitation light radiation device and a diffuse transmission area which transmits while diffusing the light emitted from the excitation light radiation device. Since light emitted from the excitation light radiation device passes through the diffuse transmission area of the optical wheel while diffusing, the excitation light radiation device is also regarded as a blue light source. Further, at a position where the light of the blue wavelength band and the light of the green wavelength band intersect with light of a red wavelength band, a dichroic mirror which transmits light of the blue wavelength band and light of the red wavelength band and reflects light of the green wavelength band is disposed.
Sometimes, in light of the red wavelength band and light of the green wavelength band, the short wavelength side of the light of the red wavelength band and the long wavelength side of the light of the green wavelength band overlap in a wavelength band. Further, sometimes, of light of the red wavelength band incident on the dichroic mirror, red light of wavelengths in a range overlapping light of the green wavelength band is reflected by the dichroic mirror. The light of the red wavelength band reflected by the dichroic mirror is discarded without being used as irradiation light. As described above, in optical systems using dichroic mirrors, sometimes, luminous efficiency of light decreases.
An object of the present invention is to provide a light source device capable of improving the light use efficiency of source light, and a projector including the light source device.